The culprit? High levels of selenium in irrigation runoff draining into Kesterson.

Fast-forward to 2010. Federal officials are still grappling with what to do with more than 300,000 San Joaquin Valley acres so loaded with selenium and other salts that, if irrigated, the land must be drained to avoid poisoning the crops. Much of this land is in the massive Westlands Water District, which produces more than 220 million heads of lettuce (among other crops) every year – more than half a head of lettuce for every person in the U.S.

There is some land that is just too expensive – economically and environmentally – to farm. The selenium-impaired acres in Westlands Water District fall in this category, as the government’s own calculations show.

When the federal Bureau of Reclamation did a cost-benefit analysis for a plan to retire some of the impaired land in Westlands (and a smaller area to the north of the district) and build drainage and treatment facilities for the remaining land, the agency calculated an economic loss of $10.2 million per year. And this estimate didn’t factor in another $10.8 million per year in U.S. Department of Agriculture crop subsidy payments, according to EWG’s analysis in a new report, “Throwing Good Money After Bad Lands.”

On the other hand, the Bureau of Reclamation figured that retiring all selenium-heavy land in Westlands and building treatment and drainage facilities for a small area to the north would net an economic gain of $3.6 million per year.

Oddly, the agency proposed to move ahead with the money-losing option. This didn’t fly with Congress or the Obama administration. Now the Bureau of Reclamation has come back with a new proposal, which involves continuing to farm some of Westlands’ tainted lands and transferring some – but not all – of the responsibility to pay for drainage to farmers.

When the bill for purifying spent irrigation water is added to the expense of annual crop subsidies, taxpayers will end up paying an exorbitant price. It would be far cheaper in the long run for the government to pay Westlands’ farmers to retire all of the selenium-tainted land and transition it to other uses. Such action would also reduce water use and protect California’s invaluable, fragile wildlife habitat.

We know that large-scale land retirement can work: a 2004 Economic Research Service review of the 20-plus year old Conservation Reserve Program found that land retirement programs often actually benefited local economies over the long-term. Westlands’ selenium-tainted farmland is the perfect place to take this successful program one step further.